1. Field of the Disclosure
The embodiments described herein relate to a method and apparatus for a downhole device connected to coiled tubing to obtain diagnostic information of a wellbore. The downhole device may be connected to the interior of the coiled tubing. Alternatively, the downhole device may be connected to an exterior carrier portion of the coiled tubing.
2. Description of the Related Art
Natural resources such as gas and oil may be recovered from subterranean formations using well-known techniques. For example, a horizontal wellbore may be drilled within the subterranean formation. After formation of the horizontal wellbore, a string of pipe, e.g., casing, may be run or cemented into the well bore. Hydrocarbons may then be produced from the horizontal wellbore.
In an attempt to increase the production of hydrocarbons from the wellbore, the casing may be perforated and fracturing fluid may be pumped into the wellbore to fracture the subterranean formation. The fracturing fluid is pumped into the well bore at a rate and a pressure sufficient to form fractures that extend into the subterranean formation, providing additional pathways through which fluids being produced can flow into the well bores. The fracturing fluid typically includes particulate matter known as a proppant, e.g., graded sand, bauxite, or resin coated sand, that may be suspended in the fracturing fluid. The proppant becomes deposited into the fractures and thus holds the fractures open after the pressure exerted on the fracturing fluid has been released.
A production zone within a wellbore may have been previously fractured, but the prior fracturing may not have adequately fractured the formation leading to inadequate production from the production zone. Even if the formation was adequately fractured, the production zone may no longer be producing at adequate levels. Over an extended period of time, the production from a previously fractured horizontal wellbore may decrease below a minimum threshold level. One technique in attempting to increase the hydrocarbon production from the wellbore may be the re-fracturing of some of the previously fractured locations of the horizontal wellbore. However, it may not be beneficial to re-fracture every previously fractured location. It may be beneficial to use a diagnostic tool to analyze the production zones in a horizontal wellbore to determine which zones should be re-fractured.
FIG. 8 shows a prior art diagnostic tool 22 conveyed into a wellbore 10 on coiled tubing 40 via a wellhead 16. The coiled tubing 40 moves the diagnostic tool 22 down the wellbore 10 along the casing 18 until the diagnostic tool 22 is positioned at a desired location. The diagnostic tool 22 is connected to the surface via a cable 14, which transmits diagnostic information obtained from the device 22. The cable 14 and diagnostic tool 22 are connected to the end of the coiled tubing 40 via a cable head 20 and connector 21. Prior to running the diagnostic tool 22 into the wellbore 10, coiled tubing 40 may be run into the wellbore 10 to conduct a clean-out procedure. The coiled tubing 40 is then tripped out of the wellhead 16 and the diagnostic tool 22 and cable 14 may be connected to the coiled tubing 40 for a second trip into the wellbore 10 with the coiled tubing 40. The positioning of the cable 14 outside of the coiled tubing 40 as well as the diagnostic tool 22 being connected to end of the coiled tubing 40 may present an increased chance the coiled tubing 40 becomes stuck within the wellbore 10. It may also be beneficial to permit a cleanout procedure and conveyance of a diagnostic tool 22 into a wellbore in a single trip of coiled tubing 40.